Drivers of vehicles sometimes cannot accurately gauge: distances ahead of or to the side of their vehicle; the position or size of their vehicle relative to other road users (such as other vehicles and cyclists); and the position or size of their vehicle relative to reduced road widths (such as gaps between cars parked on each side of a road). The difficulty in accurately gauging distances is emphasised when the distance the driver is attempting to gauge is changing; for example, due to the driver's vehicle moving, and/or another vehicle or road user moving, and/or the road having a variable, non-uniform width. It is desirable therefore to assist the driver of a vehicle in more accurately assessing whether sufficient space is available for their vehicle.
In typical motor vehicles, the way in which one road user communicates with other users of the road and pedestrians around him is limited to using: indicator and warning lights that are provided on the vehicle itself (for example, the left and right indicators, brake lights, reverse lights and hazard warning lights); a horn provided on the vehicle to sound an alert; hand gesturing; miming or lip reading between drivers; and flashing of headlights. The use of some of these “external alerts” is governed by the Highway Code and their use is clear. However, the use of some of these external alerts, for example hand gesturing and flashing of headlights can be confusing and can give rise to further uncertainty. Consider, for example, the situation of two vehicles travelling in opposite directions and both approaching a narrowing in the road. One driver may gauge the available gap ahead to be insufficient for his car and the oncoming vehicle and he may flash the headlights of his vehicle to indicate that the oncoming vehicle can progress through the gap first. However, if the driver of the oncoming vehicle gauges the gap to be sufficient for both cars, he may not understand the intended meaning behind the flash of headlights and may stop to investigate whether there is a problem with his vehicle to which the other driver was attempting to alert him. Such an example may only lead to an inconvenience as both vehicles come to a halt, but it will be recognised that more serious consequences can arise to due ineffective or misleading communications between vehicle drivers.
Additionally, the external alerts are limited in the information they can convey and in the clarity of that information. There are many situations where a typical known vehicle has no means at all, or no convenient and/or clear means, of communicating the intentions of the driver or other users of the vehicle to third party users of the road or to pedestrians. For example, when an occupant of a stationary vehicle exits the vehicle, accidents can occur if a pedestrian, cyclist or other road user fails to give the occupant sufficient room to open their door to exit the vehicle. Similarly, accidents can occur if the occupant does not carefully consider the approach of cyclists, pedestrians and other road users before opening the door.
Furthermore, even well understood external alerts, such as hazard warning lights provided on a broken down vehicle, can be deficient because other vehicles on the road need to be in relatively close proximity to the broken down car before seeing the hazard warning light. On motorways, where other vehicles are travelling at relatively high speed, the lateness with which the hazard warning lights are noticed can be too late to prevent a collision with the broken down vehicle.
Additionally, there are many situations where a typical known vehicle has no means of communicating the intentions of the driver of the vehicle to other users of the road or to pedestrians. It is desirable therefore to improve the way in which drivers of a vehicle can communicate to other road users and to improve the effectiveness and clarity of such communications.